N-benzyl-m-phenylenediamine derivatives and dyes containing said compounds

ABSTRACT

N-benzyl-m-phenylenediamine derivatives of general formula (I) or the physiologically tolerated, water-soluble salts thereof 
                         
and dyeing agents for keratin fibers containing these compounds.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to novel N-benzyl-m-phenylenediamine derivativesand to agents for dyeing keratin fibers containing these compounds.

2. Description of the Related Art

In the area of keratin fiber dyeing, particularly hair dyeing, oxidationdyes have attained substantial importance. In this case, the colorationis produced by reaction of certain developers with certain couplers inthe presence of an appropriate oxidant. Suitable developers are, inparticular, 2,5-diaminotoluene, 2-(2,5-diaminophenyl)ethyl alcohol,1-(2,5-diaminophenyl)ethyl alcohol, p-aminophenol, 1,4-diaminobenzeneand 4,5-diamino-1-(2-hydroxyethyl)pyrazole, whereas suitable couplersare, for example, resorcinol, 2-methylresorcinol, 1-naphthol,3-aminophenol, 2-amino-4-(2′-hydroxyethyl)aminoanisole,1,3-diamino-4-(2′-hydroxyethoxy)benzene and 2,4-diamino-5-fluorotoluene.

The oxidation dyes used for dyeing human hair must meet numerousrequirements in addition to that of being able to produce colorations ofthe desired intensity. For example, these dyes must be harmless from atoxicological and dermatological standpoint, and the hair colorationsobtained must have good light fastness, resistance to permanent waving,acid fastness and rubbing fastness. In any case, however, in the absenceof exposure to light, rubbing and chemicals, such colorations mustremain stable over a period of at least 4 to 6 weeks. Moreover, bycombining appropriate developers and couplers, it must be possible tocreate a wide range of different color shades.

Attempts have already been made to improve the properties ofm-phenylenediamines by introduction of substituents, In this regards thereader is referred to German Unexamined Patent Application DE 29 34 330which, among other things, describes special N-substitutedm-phenylenediamines as couplers. With the currently known dyeing agents,however, it is not possible to meet the requirements placed on dyeingagents in all respects, Hence, the need continued to exist for novelcouplers that would meet the aforesaid requirements to a particularlyhigh degree.

Surprisingly, we have now found that by use ofN-benzyl-m-phenylenediamine derivatives of general formula (I), intense,stable purple to blue color shades can be obtained.

The object of the present invention are thereforeN-benzyl-m-phenylenediamine derivatives of general formula (I) orphysiologically tolerated, water-soluble salts thereof

wherein

-   R1 denotes a halogen atom (F, Cl, Br, I), a C₁–C₄-alkoxy group, a    C₁–C₄-fluoroalkoxy group, a (C₁–C₄-alkyl)sulfamido-(C₂–C₄-alkoxy)    group, a (C₁–C₄-alkyl)sulfonyl-(C₂–C₄-alkoxy) group, a    C₂–C₄-hydroxyalkoxy group, a C₃–C₄-dihydroxyalkoxy group, a    C₁–C₆-alkyl group, a C₁–C₄-alkylthioether group, a    C₂–C₄-aminocarbonylalkoxy group, an aminoalkyl group, a    trifluoromethyl group, an —Si(CH₃)₃ group, a C₁–C₄-hydroxyalkyl    group or a C₃–C₄-dihydroxyalkyl group;-   R2 and R3 independently of each other denote hydrogen or a    (C₁–C₄)-alkyl group;-   R4, R5, R6, R7 and R8 independently of each other denote hydrogen, a    halogen atom (F, Cl, Br, I), a hydroxyl group, a (C₁–C₄)-alkoxy    group, a hydroxy-(C₂–C₄)-alkoxy group, a (C₁–C₆)-alkyl group, a    (C₁–C₄)-alkylthioether group, a mercapto group, an amino group, a    (C₁–C₆)-alkylamino group, a di(C₁–C₆)-alkylamino group, a    di-[hydroxy-(C₂–C₄)-alkyl]amino group, a hydroxy-(C₂–C₄)-alkylamino    group, a trifluoromethyl group, an acetamido group, a —C(O)CH₃    group, a —C(O)CF₃ group, an —Si(CH₃)₃ group, a hydroxy-(C₁–C₄)-alkyl    group or a dihydroxy-(C₂–C₄)-alkyl group, or R5 and R6 together form    an —O—CH₂—O— bridge; provided that the R4 and R7 groups or the R5    and R8 groups do not simultaneously denote an amino group.

Compounds of formula (I) are, for example:4-amino-2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol;4-amino-2-{[5-amino-4-(2-hydroxyethoxy)phenylamino]methyl}phenol;2-[4-amino-2-(3,5-diaminobenzylamino)phenoxy]ethanol;2-[4-amino-2-(4-dimethylaminobenzylamino)phenoxy]ethnophenoxy)ethanol;2-{4-amino-2-[(pyridin-2-ylmethyl)amino]phenoxy}ethanol;2-[4-amino-2-(2-methoxybenzylamino)phenoxy]ethanol;2-[4-amino-2-(2-aminobenzylamino)phenoxy]ethanol;3-[(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)-(2-cyanoethyl)amino]propionitrile;2-[4-amino-2-(4-aminobenzylamino)phenoxy]ethanol;2-[(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methy}phenyl)-(2-hydroxyethyl)amino]ethanol;2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}benzene-1,4-diol;2-[4-amino-2-(4-nitrobenzylamino)phenoxy]ethanol;2-[4-amino-2-(3-aminobenzylamino)phenoxy]ethanol;2-[4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenoxy)ethanol;N-(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)acetamide;4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol;2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol;3-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol;4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}benzoic acid;2-[4-amino-2-(2-morpholin-4-ylbenzylamino)phenoxy]ethanol;3-[4-amino-2-(3,5-diaminobenzylamino)phenoxy]propanol;3-[4-amino-2-(4dimethylaminobenzylamino)-phenoxy]propanol;3-[4-amino-2-(4-amino-2-[4-methoxybenzylamino)phenoxy]propanol;3-(4-amino-2-benzylaminophenoxy)propanol;3-{4-amino-2-[(pyridin-2-ylmethyl)amino]phenoxy}propanol;3-[4-amino-2-(2-methoxybenzylamino)phenoxy]propanol;3-[4amino-2-(2-aminobenzylamino)phenoxy]propanol;3-[4-amino-2-(4-aminobenzylamino)phenoxy]-propanol;3-[(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)-(2-hydroxyethyl)amino]propanol,3-[4-amino-2-(4nitrobenzylamino)phenoxy]propanol;3-[4-amino-2-(3-aminobenzylamino)phenoxy]propanol;3-(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenoxy)propanol;4-{[5-amino-2-(3-hydroxypropoxy)phenylamino]methyl}phenol;2-{[5-amino-2-(3-hydroxypropoxy)phenylamino]methyl}phenol;2-{[5-amino-2-(3-hydroxypropoxy)phenylamino]methyl}phenol;3-[4-amino-2-(2-morpholin-4-ylbenzylamino)phenoxy]propanol;N³-benzyl-1,3-diamino-4-(2-methoxyethoxy)benzene;N³-(3-aminobenzyl-1,3-diamino-4-(2-methoxyethoxy)benzene;N³-(2-aminobenzyl)-1,3-diamino-4-(2-methoxyethoxy)benzene;N³-(4-aminobenzyl)-1,3-diamino-4-(2-methoxyethoxy)benzene;3-{[5-amino-2-(2-merhoxyethoxy)phenylamino]methyl}phenol;2-{[5-amino-2-(2-methoxyethoxy)phenylamino]methyl}phenol;4-{[5-amino-2-(2-methoxyethoxy)phenylamino]methyl}phenol;N³-benzyl-1,3-diamino-4-methoxybenzene;N³-(3-aminobenzyl)-1,3-diamino-4-methoxybenzene;N³-(2-aminobenzyl)-1,3-diamino-4-methoxybenzene;N³-(4-aminobenzyl)-1,3-diamino-4-methoxybenzene;3-{[5-amino-2-methoxyphenylamino]methyl}phenol;2-{[5-amino-2-methoxyphenylamino]methyl}phenol;4-{[5-amino-2-methoxyphenylamino]methyl}phenol;N³-benzyl-1,3-diamino-4-fluorobenzene;N³-(3-aminobenzyl)-1,3-diamino-4-fluorobenzene;N³-(2-aminobenzyl)-1,3-diamino-4-fluorobenzene;N³-(4-aminobenzyl)-1,3-diamino-4-fluorobenzene;3-{[5-amino-2-fluorophenylamino]methyl}phenol;2-{[5-amino-2-fluorophenylamino]methyl}phenol, and4-{[5-amino-2-fluoro-phenylamino]methyl}phenol, as well as the saltsthereof.

Preferred compounds of formula (I) are those wherein (i) R2 and R3denote hydrogen or (ii) R1 denotes a C₂–C₄-hydroxyalkoxy group and R2and R3 denote hydrogen or (iii) R1 denotes a C₂–C₄-hydroxyalkoxy group,R2 and R3 denote hydrogen and four of the R4 to R8 groups denotehydrogen while the remaining R4 to R8 groups denote hydrogen, a methoxygroup, a hydroxyl group, a methyl group or an amino group.

Particularly preferred are the following compounds of formula (I):2-(4-amino-2-benzylaminophenoxy)ethanol;2-[4-amino-2-(2-aminobenzylamino)phenoxy]ethanol;2-[4-amino-2-(4-aminobenzylamino)phenoxy]ethanol;2-[4-amino-2-(3-aminobenzylamino)phenoxy]ethanol;4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]-methyl}phenol;3-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol and2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenol, and the saltsthereof.

The N-benzyl-m-phenylenediamine derivatives of formula (I) of theinvention can be prepared by known methods of synthesis. For example,the synthesis of the compounds of the invention can be accomplished byreductive amination of a derivative of formula (II) with an amine offormula (III) followed by elimination of the protective group

wherein Rb stands for NHRa (wherein Ra denotes a protective groupdescribed, for example, in the chapter on “Protective Groups”, inOrganic Synthesis, Chapter 7, Wiley Interscience 1991) or NH₂, and R1,R2, R3, R4, R5, R6, R7 and R8 have the same meaning as in formula (I).

The compounds of formula (I) are eminently suited as couplers in theoxidative system for dyeing keratin fibers.

Another object of the present invention are therefore agents foroxidative dyeing of keratin fibers, for example hair, furs, feathers orwool, particularly human hair, based on a developer-coupler combinationcontaining as the coupler at least one N-benzyl-m-phenylenediaminederivative of general formula (I).

The compounds of formula (I) can be used as the free bases as well as inthe form of their physiologically tolerated salts with inorganic ororganic acids, for example hydrochloric acid, sulfuric acid, phosphoricacid, acetic acid, propionic acid, lactic acid or citric acid.

The N-benzyl-m-phenylenediamine derivatives of formula (I) can bepresent in the colorant of the invention in a total amount of about0.005 to 20 wt. %, an amount of about 0.01 to 5 wt. % and particularly0.1 to 2.5 wt. % being preferred.

Preferred developers are, for example 1,4-diaminobenzene(p-phenylenediamine); 1,4-diamino-2-methylbenzene (p-toluylenediamine);1,4-diamino-2,6-dimethylbenzene; 1,4-diamino-3,5-diethylbenzene;1,4-diamino-2,5-dimethylbenzene; 1,4-diamino-2,3-dimethylbenzene;2-chloro-1,4-diaminobenzene; 1,4-diamino-2-(thiophen-2-yl)benzene;1,4-diamino-2-(thiophen-3-yl)benzene;1,4-diamino-2-(pyridin-3-yl)benzene; 2,5-diaminobiphenyl;1,4-diamino-2-methoxymethylbenzene; 1,4-diamino-2-aminomethylbenzene;1,4-diamino-2-hydroxymethylbenzene;1,4-diamino-2-(2-hydroxyethoxy)-benzene;2-[2-(acetylamino)ethoxy]-1,4-diaminobenzene; 4-phenylaminoaniline;4-dimethylaminoaniline; 4-diethylaminoaniline; 4-dipropylaminoaniline;4-[ethyl-(2-hydroxyethyl)amino]aniline;4-[di(2-hydroxyethyl)amino]aniline;4-[di(2-hydroxyethyl)amino]-2-methylaniline;4-[(2-methoxyethyl)amino]aniline; 4-[(3-hydroxypropyl)amino]aniline;4-[(2,3-dihydroxypropyl)amino]aniline;1,4-diamino-2-(2-hydroxyethyl)benzene;1,4-diamino-2-(1-hydroxyethyl)benzene;1,4-diamino-2-(1-methylethyl)benzene;1,3-bis-[(4-aminophenyl)(2-hydroxyethyl)amino]-2-propanol;1,4-bis-[(4-aminophenyl)amino]butane;1,8-bis-(2,5-diaminophenoxy)-3,6-dioxaoctane; 4-amino-phenol;4-amino-3-methylphenol; 4-amino-3-(hydroxymethyl)phenol;4-amino-3-fluorophenol; 4-methylaminophenol;4-amino-2-(aminomethyl)phenol; 4-amino-2-(hydroxymethyl)phenol;4-amino-2-fluorophenol; 4-amino-2-[(2-hydroxyethyl)amino]methylphenol;4-amino-2-methylphenol; 4-amino-2-(methoxymethyl)phenol;4-amino-2-(2-hydroxyethyl)phenol; 5-aminosalicylic acid;2,5-diaminopyridine; 2,4,5,6-tetraaminopyrimidine;2,5,6-triamino-4-(1H)-pyrimidone;4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole;4,5-diamino-1-(1-methylethyl)-1H-pyrazole;4,5-diamino-1-[(4-methylphenyl)methyl]-1H-pyrazole;1-[(4-chlorophenyl)methyl]-4,5-diamino-1H-pyrazole;4,5-diamino-1-methyl-1H-pyrazole; 2-aminophenol; 2-amino-6-methylphenol;2-amino-5-methylphenol and 2,4-dihydroxyphenol.

In addition to the couplers of formula (I), the colorant of theinvention can optionally also contain other known couplers, for exampleN-(3-dimethylaminophenyl)urea; 2,6-diaminopyridine;2-amino-4-[(2-hydroxyethyl)amino]anisole;2,4-diamino-1-fluoro-5-methylbenzene;2,4-diamino-1-methoxy-5-methylbenzene;2,4-diamino-1-ethoxy-5-methylbenzene;2,4-diamino-1-(2-hydroxyethoxy)-5-methylbenzene;2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene;2,3-diamino-6-methoxypyridine;3-amino-6-methoxy-2-(methylamino)pyridine;2,6-diamino-3,5-dimethoxypyridine; 3,5-diamino-2,6-dimethoxypyridine;1,3-diaminobenzene; 2,4-diamino-1-(2-hydroxyethoxy)benzene;1,3-diamino-4-(2,3-dihydroxypropoxy)benzene;1,3-diamino-4-(3-hydroxypropoxy)benzene;1,3-diamino-4-(2-methoxyethoxy)benzene;2,4-diamino-1,5-di(2-hydroxyethoxy)benzene;1-(2-aminoethoxy)-2,4-diaminobenzene;2-amino-1-(2-hydroxyethoxy)-4-methylaminobenzene;2,4-diaminophenoxyacetic acid; 3-[di(2-hydroxyethyl)amino]aniline;4-amino-2-di[(2-hydroxyethyl)amino]-1-ethoxybenzene;5-methyl-2-(1-methylethyl)phenol; 3-[(2-hydroxyethyl)amino]aniline;3-[(2-aminoethyl)amino]aniline; 1,3-di(2,4-diaminophenoxy)propane;di(2,4-diaminophenoxy)methane; 1,3-diamino-2,4-dimethoxybenzene;2,6-bis(2-hydroxyethyl)aminotoluene; 4-hydroxyindole;3-dimethylaminophenol; 3-diethylaminophenol; 5-amino-2-methylphenol;5-amino-4-fluoro-2-methylphenol; 5-amino-4-methoxy-2-methylphenol;5-amino-4-ethoxy-2-methylphenol; 3-amino-2,4-dichlorophenol;5-amino-2,4-dichlorophenol; 3-amino-2-methylphenol;3-amino-2-chloro-6-methylphenol; 3-aminophenol;2-[(3-hydroxyphenyl)amino]acetamide;5-[(2-hydroxyethyl)amino]-4-methoxy-2-methylphenol;5-[(2-hydroxyethyl)amino]-2-methylphenol;3-[(2-hydroxyethyl)amino]phenol; 3-[(2-methoxyethyl)amino]phenol;5-amino-2-ethylphenol; 5-amino-2-methoxyphenol;2-(4-amino-2-hydroxyphenoxy)ethanol;5-[(3-hydroxypropyl)amino]-2-methylphenol;3-[(2,3-dihydroxypropyl)amino]-2-methylphenol;3-[(2-hydroxyethyl)amino]-2-methylphenol; 2-amino-3-hydroxypyridine;2,6-dihydroxy-3,4-dimethylpyridine; 5-amino-4-chloro-2-methylphenol;1-naphthol; 2-methyl-1-naphthol; 1,5-dihydroxynaphthalene;1,7-dihydroxynaphthalene; 2,3-dihydroxynaphthalene;2,7-dihydroxynaphthalene; 2-methyl-1-naphthol acetate;1,3-dihydroxybenzene; 1-chloro-2,4-dihydroxybenzene;2-chloro-1,3-dihydroxybenzene; 1,2-dichloro-3,5-dihydroxy-4-methylbenzene; 1,5-dichloro-2,4-dihydroxybenzene;1,3-dihydroxy-2-methylbenzene; 3,4-methylenedioxyphenol;3,4-methylenedioxyaniline; 5-[(2-hydroxyethyl)amino]-1,3-benzodioxole;6-bromo-1-hydroxy-3,4-methylenedioxybenzene; 3,4-diaminobenzoic acid;3,4-dihydro-6-hydroxy-1,4(2H)-benzoxazine;6-amino-3,4-dihydro-1,4[2H]-benzoxazine; 3-methyl-1-phenyl-5-pyrazolone;5,6-dihydroxyindole; 5,6-dihydroxyindoline; 5-hydroxyindole;6-hydroxyindole; 7-hydroxyindole and 2,3-indolinedione.

The couplers and developers can be present in the colorant of theinvention either individually or in admixture with one another, thetotal amount of each of the couplers and developers in the colorant ofthe invention being about 0.005 to 20 wt. % preferably about 0.01 to 5wt. % and particularly 0.1 to 2.5 wt. % (based on the total amount ofcolorant). The total amount of the developer-coupler combinationcontained in the colorant described herein is preferably about 0.01 to20 wt. %, an amount of about 0.02 to 10 wt. % and especially 0.2 to 6wt. % being particularly preferred. In general, the developers andcouplers are used in approximately equimolar amounts. It is notdisadvantageous, however, if the developers are present in a certainexcess or deficiency [for example in a (coupler : developer) ratio of1:2 to 1:0.5].

Moreover, the colorant of the invention can also contain other dyecomponents, for example 6-amino-2-methylphenol and2-amino-5-methylphenol, as well as common direct dyes, for exampletriphenylmethane dyes such as4-[(4′-aminophenyl)-(4′-imino-2″,5″-cyclohexadien-1″-ylidene)methyl]-2-methylaminobenzenemonohydrochloride (Color Index [C.I.] 42 510) and4-[(4′-amino-3′-methylphenyl)-(4″-imino-3″-methyl-2″,5″-cyclohexadien-1″-ylidene)methyl)-2-methylaminobenzenemonohydrochloride (C.I. 42 520), aromatic nitro dyes such as4-(2′-hydroxyethyl)aminonitrotoluene; 2-amino-4,6-dinitrophenol;2-amino-5-(2′-hydroxyethyl)aminonitrobenzene;2-chloro-6-(ethylamino)-4-nitrophenol;4-chloro-N-(2-hydroxyethyl)-2-nitroaniline;5-chloro-2-hydroxy-4-nitroaniline; 2-amino-4-chloro-6-nitrophenol and1-(2′-ureidoethyl)amino-4-nitrobenzene, azo dyes such as sodium6-[(4′-aminophenyl)azo]-5-hydroxynaphthalene-1-sulfonate (C.I. 14 805)and disperse dyes, for example 1,4-diaminoanthraquinone and1,4,5,8-tetraaminoanthraquinone. The colorants of the invention cancontain the aforesaid dye components in an amount from about 0.1 to 4wt. %.

The couplers and developers as well as the other dye components,provided they are bases, can, of course, also be used in the form oftheir physiologically tolerated salts with organic or inorganic acids,for example hydrochloric acid or sulfuric acid, or—if they containaromatic OH groups—in the form of their salts with bases, for example asalkali metal phenoxides.

Moreover, if the colorants of the invention are to be used for coloringhair, they can also contain other common cosmetic additives, for exampleantioxidants such as ascorbic acid, thioglycolic acid or sodium sulfite,as well as perfume oils, complexing agents, wetting agents, emulsifiers,thickeners and hair-care agents.

The colorant of the invention can be in the form of, for example, asolution, particularly an aqueous or aqueous-alcoholic solution. Aparticularly preferred formulation form, however, is a cream, gel oremulsion. Such a composition consists of a mixture of the dye componentsand the usual additives employed for such compositions.

Common additives to solutions, creams, emulsions or gels are, forexample solvents such as water, lower aliphatic alcohols, for exampleethanol, propanol or isopropanol, glycerol or glycols such as1,2-propylene glycol, moreover wetting agents or emulsifiers from theclasses of anionic, cationic, amphoteric or nonionic surface-activeagents, for example fatty alcohol sulfates, ethoxylated fatty alcoholsulfates, alkylsulfonates, alkylbenzenesulfonates,alkyltrimethylammonium salts, alkylbetaines, ethoxylated fatty alcohols,ethoxylated nonylphenols, fatty acid alkanolamides and ethoxylated fattyesters, furthermore thickeners such as the higher fatty alcohols,starch, cellulose derivatives, petrolatum, paraffin oil and fatty acids,also hair-care agents such as cationic resins, lanolin derivatives,cholesterol, pantothenic acid and betaine. The said constituents areused in amounts commonly employed for such purposes, for example thewetting agents and emulsifiers at a concentration of about 0.5 to 30 wt.%, the thickeners in an amount from about 0.1 to 25 wt. % and thehair-care agents at a concentration from about 0.1 to 5 wt. %.

Depending on the composition, the colorant of the invention can beweakly acidic, neutral or alkaline. In particular, it has a pH of 6.5 to11.5. Adjustment to a basic pH is preferably done with ammonia, but itcan also be done with an organic amine, for example monoethanolamine andtriethanolamine, or with an inorganic base such as sodium hydroxide andpotassium hydroxide. Suitable for adjustment to an acidic pH areinorganic or organic acids, for example phosphoric acid, acetic acid,citric acid or tartaric acid.

For oxidative dyeing of hair, the afore-described colorant is mixed withan oxidant just before use, and the resulting mixture is applied to hairin an amount sufficient for the hair-dyeing treatment, in general about50 to 200 grams, depending on the hair fullness. The ready-to-useoxidative hair colorant obtained after mixing with the oxidantpreferably has a pH of 6.5 to 11.5.

Suitable oxidants for developing the hair coloration are mainly hydrogenperoxide or its products of addition to urea, melamine, sodium borate orsodium carbonate, in the form of a 3–12%, preferably 6% aqueoussolution, atmospheric oxygen also being suitable. When a 6% hydrogenperoxide solution is used as oxidant, the weight ratio of hair colorantto oxidant is from about 5:1 to 1:2, but preferably about 1:1. Largeramounts of oxidant are used primarily at higher dye concentrations inthe hair colorant or when stronger bleaching of the hair is wanted atthe same time. The mixture is allowed to act on the hair at 15 to 50° C.for about 10 to 45 min, preferably 30 min, after which the hair isrinsed with water and dried. Optionally, following this rinsing, thehair is washed with a shampoo and optionally post-rinsed with a weakorganic acid, for example citric acid or tartaric acid. The hair is thendried.

The colorants of the invention containing an N-benzyl-m-phenylenediaminederivative of formula (I) as coupler give hair colorations of excellentcolor stability, particularly in terms of light fastness, wash fastnessand rubbing fastness. As far as the dyeing properties are concerned, thehair colorants of the invention provide a wide range of different shadesfrom blond to brown, purple, violet and even blue and black, dependingon the the kind and composition of the dye components. The shades arenoteworthy for their high color intensity. The very good coloringproperties of the hair colorant of the present patent application alsomanifest themselves in that this colorant makes it possible to dye grayhair, previously not damaged chemically, without any problems and withgood covering power.

The N-benzyl-m-phenylenediamine derivatives of formula (I) are highlywater-soluble and give colorations of high color intensity and excellentcolor stability, particularly in terms of light fastness, wash fastnessand rubbing fastness. Moreover, they have excellent storage stability,particularly as constituents of the oxidation colorants describedherein.

The following examples illustrate the object of the invention in greaterdetail without limiting its scope.

EXAMPLES Example 1

A. Synthesis of tert.butyl[3-amino-4-(2-hydroxyethoxy)phenyl]carbamate

To a solution of 10.7 g (100 mmol) of 2-(2,4-diaminophenoxy)ethanol in300 mL of acetonitrile was added dropwise a solution of 16.8 g of NaHCO₃in 100 mL of water, followed by the addition of 22 g (100 mmol) ofditert.butyl dicarbonate. The reaction mixture was allowed to agitatefor 6 hours. At the end of the reaction, the reaction mixture was pouredinto 100 mL of dichloromethane, and the organic phase was extracted withdilute hydrochloric acid. The aqueous phase was then made alkaline withsaturated 2N sodium hydroxide solution [sic−Translator] and thenextracted with dichloromethane. The organic phase was dried over sodiumsulfate and then distilled off in a rotary evaporator.

This gave 10.3 g (38% of the theoretical) oftert.butyl[3-amino-4-(2-hydroxyethoxy)-phenyl]carbamate.

¹H-NMR (300 MHz, CDCl₃): δ=7.26 (br s, 1H); 6.95 (d, 1H); 6.72 (d, 1H);6.34 (s, 1H); 4.77 (m, 2H); 3.9 (m, 2H); 1.50 (s, 9H).

B. Synthesis of the 1,3-diaminobenzene derivatives.

0.031 g (0.15 mmol) of the tert.butyl (3-aminophenyl)carbamate fromExample 1A and 0.1 mmol of the appropriate aldehyde were dissolved inmethanol (dried over molecular sieve). Following the addition of 10 mgof molecular sieve, the reaction mixture was allowed to agitate for 7hours. Then, 0.3 mL of a solution of borane-tetrahydrofuran complex (1 Min tetrahydrofuran) was added at 0° C., and the reaction mixture wasallowed to agitate one hour at room temperature. At the end of thereaction, the reaction mixture was poured into water and extracted withethyl acetate. The organic phase was dried with magnesium sulfate. Thesolvent was distilled off in a rotary evaporator, and the residue waspurified on silica gel with petroleum ether/ethyl acetate (1:1). Theresulting product in 4 mL of ethanol and 1.5 mL of a 2.9-molar ethanolichydrochloric acid solution was heated to 50° C. The precipitate wasfiltered off, washed twice with 1-mL portions of ethanol and then dried.

a. 2-(4-Amino-2-benzylaminophenoxy)ethanol hydrochloride

Aldehyde used: benzaldehyde

Mass spectrum: MH⁺ 259 (100)

b. 2-[4-Amino-2-(4-aminobenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: tert.butyl (4-formylphenyl)carbamate

Mass spectrum: MH⁺ 274 (25)

c. 2-[4-Amino-2-(3-aminobenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 3-aminobenzaldehyde

Mass spectrum: MH⁺ 274 (80)

d. 2-[4-Amino-2-(2-aminobenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 2-aminobenzaldehyde

Mass spectrum: MH⁺ 274 (10)

e. 4-Amino-2-{[5-amino-2(4)-(2-hydroxyethoxy)phenylamino]methyl}phenolhydrochloride

Aldehyde used: tert.butyl (3-formyl-4-hydroxyphenyl)carbamate

Mass spectrum: MH⁺ 293 (100)

f. 2-[4-Amino-2-(3,5-diaminobenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 3,5 diaminobenzaldehyde

Mass spectrum: MH⁺ 289 (100)

g. 2-[4-Amino-2-(4-dimethylaminobenzylamino)phenoxy]ethanol

Aldehyde used: 4-dimethylaminobenzaldehyde

Mass spectrum: MH⁺ 302 (10)

h. 2-[4-Amino-2-(4-methoxvbenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 4-methoxybenzaldehyde

Mass spectrum: MH⁺ 229 (100)

i. 2-[4-Amino-2-(2-methoxybenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 2-methoxybenzaldehyde

Mass spectrum: MH⁺ 229 (100)

j.3-[(4-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)-(2-cyanoethyl)amino]propionitrilehydrochloride

Aldehyde used: 3-[(2-cyanoethyl)-(4-formylphenyl)amino]propionitrile

Mass spectrum: MH⁺ 380 (100)

k.2-[(4-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)-(2-hydroxyethyl)amino]ethanolhydrochloride

Aldehyde used: 4-[bis-(2-hydroxyethyl)amino]benzaldehyde

Mass spectrum: MH⁺ 362 (10)

l.1,4-Dihydroxy-2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]methyl}benzenehydrochloride

Aldehyde used: 2,5-dihydroxybenzaldehyde

Mass spectrum: MH⁺ 291 (50)

m. 2-[4-Amino-2-(4-nitrobenzylamino)phenoxy]ethanol hydrochloride

Aldehyde used: 4-nitrobenzaldehyde

Mass spectrum: MH⁺ 304 (20)

n. 2-(4-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenoxy)ethanolhydrochloride

Aldehyde used: 4-(2-hydroxyethoxy)benzaldehyde

Mass spectrum: MH⁺ 319 (100)

o. N-(4-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenyl)acetamidehydrochloride

Aldehyde used: 4-acetamidobenzaldehyde

Mass spectrum: MH⁺ 316 (100)

p. 4-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenolhydrochloride

Aldehyde used: 4-hydroxybenzaldehyde

Mass spectrum: MH⁺ 275 (80)

q. 3-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenolhydrochloride

Aldehyde used: 3-hydroxybenzaldehyde

Mass spectrum: MH⁺ 203 (100)

r. 2-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}phenolhydrochloride

Aldehyde used: 2-hydroxybenzaldehyde

Mass spectrum: MH⁺ 275 (40)

s. 2-{[5-Amino-2-(2-hydroxyethoxy)phenylamino]methyl}benzoic acidhydrochloride

Aldehyde used: 4-formylbenzoic acid

Mass spectrum: MH⁺ 303 (45)

t. 2-[4-Amino-2-(2-morpholin-4-ylbenzylamino)phenoxy]ethanolhydrochloride

Aldehyde used: 2-(morpholin-4-yl)benzaldehyde

[Mass spectrum missing·Translator]

u. Synthesis of 2-[2-amino-4-(benzylamino)phenoxy]ethanol

2.66 g (10 mmol) of 2-(2,4-diaminophenoxy)ethanol and 1.06 g (10 mmol)of benzaldehyde were dissolved in methanol (dried over molecular sieve).After addition of 10 mg of molecular sieve, the reaction mixture wasallowed to agitate 7 hours. Then, 20 mL of a solution ofborane-tetrahydrofuran com-plex (1 M in tetrahydrofuran) was added at 0°C., and the reaction mixture was allowed to agitate one hour at roomtemperature. At the end of the reaction, the reaction mixture wasfiltered and hydrolyzed. The precipitate was filtered off, washed withwater and then dried.

¹H-NMR (300 MHz, D₆MSO): δ=7.21 (m, 5H); 6.56 (d, 1H); 6.0 (s, 1H); 5.83(d, 1H); 4.77 (s, 2H); 3.7 (t, 2H); 3.63 (t, 2H).

Examples 2 to 23 Hair Colorants

Hair colorant solutions having the following composition were prepared:

1.25 mmol of coupler of formula (I) as per Table 1 1.25 mmol ofdeveloper as per Table 1 1.0 g of potassium oleate (8% aqueous solution)1.0 g of ammonia (22% aqueous solution) 1.0 g of ethanol 0.3 g ofascorbic acid to 100.0 g water

Just before use, 50 g of the foregoing coloring solution was mixed with50 g of a 6% aqueous hydrogen peroxide solution. The mixture was thenapplied to bleached hair. After an exposure time of 30 min at 40° C.,the hair was rinsed with water, washed with a commercial shampoo anddried. The resulting color shades are presented in Table 1.

TABLE 1 Developer III. IV. I. II. 2,5-Diamino- 4,5-Diamino- Coupler1,4-Di- 2,5-Diamino- phenyl- 1-(2′-hydroxy- Example of formula amino-toluene ethanol ethyl)pyrazole No. (I) benzene sulfate sulfate sulfate 2As per Ex. 1a dark blue dark blue dark blue purple shades 4 As per Ex.1b dark blue dark blue dark blue purple shades 5 As per Ex. 1c dark bluedark blue dark blue purple shades 6 As per Ex. 1d dark blue dark bluedark blue purple shades 7 As per Ex. 1e dark blue blue blue purpleshades 8 As per Ex. 1f dark blue dark blue dark blue purple shades 9 Asper Ex. 1g dark blue blue blue purple shades 10 As per Ex. 1h dark blueblue blue purple shades 11 As per Ex. 1i dark blue blue blue purpleshades 12 As per Ex. 1j blue sl. blue sl. blue purple shades 13 As perEx. 1k blue blue blue purple shades 14 As per Ex. 1l blue sl. blue sl.blue purple shades 15 As per Ex. 1m blue blue blue purple shades 16 Asper Ex. 1n blue blue blue purple shades 17 As per Ex. 1o blue blue bluepurple shades 18 As per Ex. 1p blue blue blue purple shades 19 As perEx. 1q blue blue blue purple shades 20 As per Ex. 1r blue blue bluepurple shades 21 As per Ex. 1s blue sl. blue sl. blue purple shades 22As per Ex. 1t blue sl. blue sl. blue purple shades 23 As per Ex. 1u blueblue blue purple shades

Examples 24 to 35 Hair Colorants

Hair colorant solutions of the following composition were prepared:

X g of 1,3-diaminobenzene [coupler K1 to K3 of formula (I) as per Table4] U g of developer E8 to E15 as per Table 2 Y g of coupler K12 to K36as per Table 4 Z g of direct dye D2 as per Table 3 10.0 g of potassiumoleate (8% aqueous solution) 10.0 g of ammonia (22% aqueous solution)10.0 g of ethanol 0.3 g of ascorbic acid to 100.0 g water

Just before use, 30 g of the foregoing coloring solution was mixed with30 g of a 6% aqueous solution of hydrogen peroxide. The mixture was thenapplied to bleached hair. After an exposure time of 30 min at 40° C.,the hair was rinsed with water, washed with a commercial shampoo anddried. Table 5 shows the coloring results.

Examples 36 to 47 Hair Colorants

Dye carriers in cream form and having the following composition wereprepared:

X g of 1,3-diaminobenzene (coupler K1 to K3 of formula (I) as per Table4) U g of developer E8 to E15 as per Table 2 Y g of coupler K12 to K36as per Table 4 Z g of direct dye D2 as per Table 3 15.0 g of cetylalcohol 0.3 g of ascorbic acid 3.5 g of sodium lauryl alcohol diethyleneglycol ether sulfate, 28% aqueous solution 3.0 g of ammonia, 22% aqueoussolution 0.3 g of sodium sulfite, anhydrous to 100.0 g water

Just before use, 30 g of the foregoing coloring cream was mixed with 30g of a 6% solution of hydrogen peroxide. The mixture was then applied tothe hair. After an exposure time of 30 min at 40° C., the hair wasrinsed with water, washed with a commercial shampoo and dried. Thecoloring results are presented in Table 6.

TABLE 2 Developers E8 1,4-diaminobenzene E91,4-diamino-2-(2-hydroxyethyl)benzene sulfate E12 4-aminophenol E13N,N-bis(2′-hydroxyethyl)-p-phenylenediamine sulfate E144,5-diamino-1-(2′-hydroxyethyl)pyrazole sulfate E15 2,5-diaminotoluenesulfate

TABLE 3 Direct Dye D2 6-chloro-2-ethylamino-4-nitrophenol

TABLE 4 Couplers K1 2-(4-amino-2-benzylaminophenoxy)ethanolhydrochloride K2 2-[4-amino-2-(4-aminobenzylamino)phenoxy]ethanolhydrochloride K3 4-amino-2-{[5-amino-2 or4-(2-hydroxyethoxy)phenylamino]- methyl}-phenol hydrochloride K122-amino-4-(2′-hydroxyethyl)aminoanisole sulfate K131,3-diamino-4-(2-hydroxyethoxy)benzene sulfate K21 3-aminophenol K225-amino-2-methylphenol K23 3-amino-2-chloro-6-methylphenol K311,3-dihydroxybenzene K32 2-methyl-1,3-dihydroxybenzene K331-chloro-2,4-dihydroxybenzene K36 2-amino-5-methylphenol

TABLE 5 Hair Colorants Example No. 24 25 26 27 28 29 Dyes (Quantity ofdye in grams) K1 0.15 0.16 0.09 0.12 0.15 0.18 E8 0.30 E9 0.25 0.30 E150.25 0.30 0.25 K12 0.05 K13 0.05 K21 0.05 K22 0.05 K23 0.05 0.10 0.100.10 K31 0.20 0.15 0.20 0.10 K32 0.20 0.10 0.10 K33 0.20 K36 0.03 0.05Dyeing blond blond blond blond blond blond result Example No. 30 31 3233 34 35 Dyes (Quantity of dye in grams) K2 0.15 0.09 0.15 0.12 K3 0.160.12 0.16 E8 0.30 E9 0.25 0.30 E15 0.25 0.30 0.25 K12 0.05 K13 0.05 K210.05 K22 0.05 K23 0.05 0.10 0.10 0.10 K31 0.20 0.15 0.20 0.10 K32 0.200.10 0.10 K33 0.20 Dyeing blond blond blond blond blond blond result

TABLE 6 Hair Colorants Example No. 36 37 38 39 40 41 Dyes (Quantity ofdye in grams) K1 0.70 1.50 1.25 0.18 0.18 0.18 E8 1.50 E13 1.60 0.70 E151.80 0.70 0.70 K12 0.60 K23 0.05 0.10 0.10 0.10 K31 1.10 1.10 1.10 0.400.40 0.40 D2 0.10 0.10 0.10 Dyeing black black black brown brown brownresult Example No. 42 43 44 45 46 47 Dyes (Quantity of dye in grams) K20.7 1.15 0.15 K3 1.5 0.18 0.18 E8 1.5 E13 1.6 0.7 E15 1.8 0.7 0.7 K120.6 K23 0.05 0.10 0.10 0.10 K31 1.10 1.10 1.10 0.40 0.40 0.40 D2 1.101.10 1.10 Dyeing black black black brown brown brown result Unlessotherwise indicated, all percentages given in the present patentapplication are by weight.

1. An N-Benzyl-m-phenylenediamine derivatives of general formula (I) orthe physiologically-tolerated, water-soluble salts thereof,

wherein R1 denotes a halogen atom, a C₁–C₄-alkoxy group, aC₁–C₄-fluoroalkoxy group, a (C₁–C₄-alkyl)sulfamido-(C₂–C₄-alkoxy) group,a (C₁–C₄-alkyl)sulfonyl-(C₂–C₄-alkoxy) group, a C₂–C₄-hydroxyalkoxygroup, a C₃–C₄-dihydroxyalkoxy group, a C₁–C₆-alkyl group, aC₁–C₄-alkylthioether group, a C₂–C₄-aminocarbonylalkoxy group, anaminoalkyl group, a trifluoromethyl group, an —Si(CH₃)₃ group, aC₁–C₄-hydroxyalkyl group or a C₃–C₄-dihydroxyalkyl group; R2 and R3independently of each other denote hydrogen or a C₁–C₄-alkyl group, R4,R5, R6, R7 and R8 independently of each other denote hydrogen , ahalogen atom, a hydroxyl group, a (C₁–C₄)-alkoxy group, ahydroxy-(C₂–C₄)-alkoxy group, a (C₁–C₆)-alkyl group, a(C₁–C₄)-alkylthioether group, a mercapto group, an amino group, a(C₁–C₆)-alkylamino group, a di(C₁–C₆)-alkylamino group, adi[hydroxy-(C₂–C₄)-alkyl]amino group, a hydroxy-(C₂–C₄)-alkylaminogroup, a trifluoromethyl group, an acetamido group, a —C(O)Ch₃ group, a—C(O)Cf₃ group, an —Si(CH₃)₃ group, a hydroxy-(C₁–C₄)-alkyl group or adihydroxy-(C₂–C₄)-alkyl group, or R5 and R6 together form an —O—CH₂—O—bridge; with the proviso that R4 and R7 do not simultaneously eachdenote an amino group or that R5 and R8 do not simultaneously eachdenote an amino group; that R1 does not denote a CH₃ group when each ofR2, R3, R4, R5, R8, R7 and R8 denotes hydrogen; that R1 does not denotea OCH₃ group when simultaneously R2 denotes an isopropyl group and eachof R3, R4, R5, R6, R7 and R8 denote hydrogen; that R1 does not denotehydrogen when simultaneously R2 denotes an isopropyl group, R4 denotesbromine and each of R3, R5, R6, R7 and R8 denote hydrogen or R8 denotesbromine and each of R3, R4, R5, R6 and R7 denote hydrogen; and that R1does not denote methyl when simultaneously R2 denotes an isopropylgroup, R4 denotes bromine and each of R3, R5, R6, R7 and R8 denotehydrogen or RB denotes bromine and each of R3, R4, R5, R6 and R7 denotehydrogen.
 2. An N-benzyl-m-phenylenediamine derivative, or awater-soluble salt thereof, wherein said N-benzyl-m-phenylenediaminederivative is selected from the group consisting of4-amino-2-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,4-amino-2-{[5-amino-4-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,2-[4-amino-2-(3,5-diamino-benzylamino)phenoxy]ethanol,2-[4-amino-2-(4-dimethylamino-benzylamino)-phenoxy]-ethanol,2-[4-amino-2-(4-methoxy-benzylamino)-phenoxy]-ethanol,2-(4-amino-2-benzyl-aminophenoxy)-ethanol,2-{4-amino-2-[(pyridin-2-ylmethyl)-amino]-phenoxy}-ethanol,2-[4-amino-2-(2-methoxy-benzylamino)-phenoxy]-ethanol,2-[4-amino-2-(2-amino-benzyl-amino)phenoxy]-ethanol,3-[(4-{[5-amino-2-(2-hydroxy-ethoxy)-phenylamino]-methyl}-phenyl)-(2-cyanoethyl)-amino]-propionitrile,2-[4-amino-2-(4-amino-benzylamino)-phenoxy]ethanol,2-[(4-{[5-amino-2-(2-hydroxyethoxy)phenyl-amino]methyl}-phenyl)-(2-hydroxyethyl)amino]-ethanol,2-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-benzene-1,4-diol,2-[4-amino-2-(4-nitrobenzylamino)-phenoxy]-ethanol,2-[4-amino-2-(3-aminobenzylamino)-phenoxy]-ethanol,2-(4-{[5-amino-2-(2-hydroxy-ethoxy)phenyl-amino]-methyl}-phenoxy)-ethanol,N-(4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenyl)-acetamide,4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,3-{(5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenol,2-{[5-amino-2-(2-hydroxy-ethoxy)-phenylamino]-methyl}-phenol,4-{[5-amino-2-(2-hydroxyethoxy)-phenyl-amino]-methyl}-benzoic acid,2-[4-amino-2-(2-morpholin-4-yl-benzylamino)-phenoxyethenol,3-[4-amino-2-(3,5-diamino-benzylamino)phenoxy]-propanol,3-[4-amino-2-(4-dimethylaminobenzylamino)-phenoxy]-propanol,3-(4-amino-2-(4-methoxybenzylamino)-phenoxy]-propanol,3-(4-amino-2-benzlamino-phenoxy)-propanol,3-{4-amino-2-[(pyridin-2-ylmethyl)-amino]phenoxy}-propanol,3-[4-amino-2-(2-methoxybenzylamino)phenoxy]-propanol,3-[4-amino-2-(2-aminobenzylamino)phenoxy]-propanol,3-[4-amino-2-(4-aminobenzyl-amino)-phenoxy]-propanol,3-[(4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenyl)-(2-hydroxyethyl)amino]propanol,3-[4-amino-2-(4-nitrobenzyl-amino)-phenoxy]-propanol,3-[4-amino-2-(3-aminobenzylamino)-phenoxy]-propanol,3-(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]-methyl}-phenoxy)-propanol,4-{[5-amino-2-(3-hydroxypropoxy)phenylamino]-methyl}-phenol,2-{[5-amino-2-(3-hydroxy-propoxy)phenylamino]-methyl}-phenol,2-{[5-amino-2-(3-hydroxypropoxy)-phenylamino]-methyl}-phenol,3-[4-amino-2-(2-morpholin-4-yl-benzylamino)-phenoxy]-propanol,N³-benzyl-1,3-diamino-4-(2-methoxy-ethoxy)-benzene,N³-(3-aminobenzyl)-1,3-diamino-4-(2-methoxy-ethoxy)-benzene,N³-(2-amino-benzyl)-1,3-diamino-4-(2-methoxyethoxy)-benzene,N³-(4-aminobenzyl)-1,3-diamino-4-(2-methoxyethoxy)-benzene,3-{[5-amino-2-(2-methoxyethoxy)-phenylamino]methyl}-phenol,2-{[5-amino-2-(2-methoxy-ethoxy)-phenylamino]-methyl}phenol,4-{[5-amino-2-(2-methoxy-ethoxy)-phenyl-amino]-methyl}-phenol,N³-benzyl-1,3-diamino-4-methoxy-benzene,N³-(3-amino-benzyl)-1,3-diamino-4-methoxybenzene,N³-(2-aminobenzyl)-1,3-diamino-4-methoxybenzene,N³-(4-aminobenzyl)-1,3-diamino-4-methoxybenzene,3-{[5-amino-2-methoxy-phenylamino]-methyl}-phenol,2-{[5-amino-2-methoxy-phenylamino]-methyl}-phenol,4-{[5-amino-2-methoxy-phenyl-amino]-methyl}-phenol,N³-benzyl-1,3-diamino-4-fluorobenzene,N³-(3-aminobenzyl)-1,3-diamino-4-fluorobenzene,N³-(2-aminobenzyl)-1,3-diamino-4-fluorobenzene,N³-(4-amino-benzyl)-1,3-diamino-4-fluorobenzene,3-{[5-amino-2-fluoraphenylamino]-methyl}-phenol,2-{[5-amino-2-fluorophenyl-amino]-methyl}-phenol, and4-{[5-amino-2-fluoro-phenylamino]methyl}-phenol.
 3. TheN-benzyl-m-phenylenediamine derivative, or the water-soluble saltthereof, as defined in claim 1, wherein R2 and R3 each denote hydrogen;R1 denotes a C₂–C₄-hydroxyalkoxy group and R2 and R3 each denotehydrogen; or R1 denotes a C₂–C₄-hydroxyalkyl group, R2 and R3 eachdenote hydrogen and four of R4, R5, R6, R7 and R8 denote hydrogen whilea remaining one of R4, R5, R6, R7 and R8 denotes hydrogen, a methoxygroup, a hydroxy group, a methyl group or an amino group.
 4. TheN-benzyl-m-phenylenediamine derivative, or the water-soluble saltthereof, as defined in claim 1, wherein said N-benzyl-m-phenylenediaminederivative is selected from the group consisting of2-(4-amino-2-benzylamino-phenoxy)ethanol,2-[4-amino-2-(2-aminobenzylamino)phenoxy]-ethanol,2-[4-amino-2-(4-aminobenzylamino)phenoxy]ethanol,2-[4-amino-2-(3-amino-benzylamino)phenoxy]ethanol,4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}phenol,3-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}phenol, and2-{[5-amino-2-(2-hydroxyethoxy)phenylamino]-methyl}phenol.
 5. Acomposition for oxidative dyeing of keratin fibers, said compositioncontaining at least one coupler and at least one developer; wherein saidat least one coupler comprises at least one N-benzyl-m-phenylenediaminederivative of formula (I), or a physiologically tolerated, water-solublesalt thereof,

wherein R1 denotes a halogen atom, a C₁–C₄-alkoxy group, aC₁–C₄-fluoroalkoxy group, a (C₁–C₄-alkyl)sulfamido-(C₂–C₄-alkoxy) group,a (C₁–C₄-alkyl)sulfonyl-(C₂–C₄-alkoxy) group, a C₂–C₄-hydroxyalkoxygroup, a C₃–C₄-dihydroxyalkoxy group, a C₁–C₆-alkyl group, aC₁–C₄-alkylthioether group, a C₂–C₄-aminocarbonylalkoxy group, anaminoalkyl group, a trifluoromethyl group, an —Si(CH₃)₃ group, aC₁–C₄-hydroxyalkyl group or a C₃–C₄-dihydroxyalkyl group; R2 and R3independently of each other denote hydrogen or a C₁–C₄-alkyl group, R4,R5, R6, R7 and R8 independently of each other denote hydrogen , ahalogen atom, a hydroxyl group, a (C₁–C₄)-alkoxy group, ahydroxy-(C₂–C₄)-alkoxy group, a (C₁–C₆)-alkyl group, a(C₁–C₄)-alkylthioether group, a mercapto group, an amino group, a(C₁–C₆)-alkylamino group, a di(C₁–C₆)-alkylamino group, adi[hydroxy-(C₂–C₄)-alkyl]amino group, a hydroxy-(C₂–C₄)-alkylaminogroup, a trifluoromethyl group, an acetamido group, a —C(O)Ch₃ group, a—C(O)CF₃ group, an —Si(CH₃)₃ group, a hydroxy-(C₁–C₄)-alkyl group or adihydroxy-(C₂–C₄)-alkyl group, or R5 and R6 together form an —O—CH₂—O—bridge; with the proviso that R4 and R7 do not simultaneously eachdenote an amino group or that R5 and R8 do not simultaneously eachdenote an amino group; that R1 does not denote a CH₃ group when each ofR2, R3, R4, R5, R8, R7 and R8 denotes hydrogen; that R1 does not denotea OCH₃ group when simultaneously R2 denotes an isopropyl group and eachof R3, R4, R5, R6, R7 and R8 denote hydrogen; that R1 does not denotehydrogen when simultaneously R2 denotes an isopropyl group, R4 denotesbromine and each of R3, R5, R6, R7 and R8 denote hydrogen or R8 denotesbromine and each of R3, R4, R5, R6 and R7 denote hydrogen.
 6. Thecomposition as defined in claim 5, containing from 0.005 to 20 percentby weight of said at least one N-benzyl-m-phenylenediamine derivative offormula (I), or said physiologically tolerated, water-soluble saltthereof.
 7. The composition as defined in claim 5, wherein said at leastone developer is selected from the group consisting of1,4-diaminobenzene; 1,4-diamino-2-methylbenzene;1,4-diamino-2,6-dimethylbenzene; 1,4-diamino-3,5-diethyl-benzene;1,4-diamino-2,5-dimethylbenzene; 1,4-diamino-2,3-dimethylbenzene;2-chloro-1,4-diaminobenzene; 1,4-diamino-2-(thiophen-2-yl)benzene;1,4-diamino-2-(thiophen-3-yl)benzene;1,4-diamino-2-(pyridin-3-yl)benzene; 2,5-diaminobiphenyl;1,4-diamino-2-methoxymethylbenzene; 1,4-diamino-2-aminomethyl-benzene;1,4-diamino-2-hydroxymethylbenzene;1,4-diamino-2-(2-hydroxyethoxy)benzene;2-[2-(acetylamino)ethoxy]-1,4-diaminobenzene; 4-phenylaminoaniline;4-dimethylaminoaniline; 4-diethylaminoaniline; 4-dipropyl-aminoaniline;4-[ethyl-(2-hydroxyethyl)amino]aniline;4-[di(2-hydroxyethyl)amino]-aniline;4-[di(2-hydroxy-ethyl)amino]-2-methylaniline;4-[(2-methoxyethyl)amino]-aniline; 4-[(3-hydroxy-propyl)amino]aniline;4-[(2,3-dihydroxypropyl)amino]-aniline;1,4-diamino-2-(2-hydroxyethyl)benzene;1,4-diamino-2-(1-hydroxyethyl)-benzene;1,4-diamino-2-(1-methylethyl)benzene;1,3-bis[(4-aminophenyl)-(2-hydroxyethyl)amino]-2-propanol;1,4-bis[(4-aminophenyl)-amino]butane;1,8-bis(2,5-diaminophenoxy)-3,6-dioxaoctane; 4-aminophenol;4-amino-3-methylphenol; 4-amino-3-(hydroxymethyl)phenol;4-amino-3-fluorophenol; 4-methyl-aminophenol;4-amino-2-(aminomethyl)phenol; 4-amino-2-(hydroxymethyl)-phenol;4-amino-2-fluorophenol; 4-amino-2-[(2-hydroxyethyl)-amino)methyl-phenol;4-amino-2-methylphenol; 4-amino-2-(methoxymethyl)phenol;4-amino-2-(2-hydroxyethyl)phenol; 5-aminosalicylic acid;2,5-diaminopyridine; 2,4,5,6-tetraaminopyrimidine;2,5,6-triamino-4-(1H)-pyrimidone;4,5-diamino-1-(2-hydroxyethyl)-1H-pyrazole;4,5-diamino-1-(1-methylethyl)-1H-pyrazole;4,5-diamino-1-[(4-methylphenyl)methyl]-1H-pyrazole;1-[(4-chlorophenyl)methyl]-4,5-diamino-1H-pyrazole;4,5-diamino-1-methyl-1H-pyrazole; 2-aminophenol; 2-amino-6-methylphenol;2-amino-5-methylphenol and 2,4-dihydroxyphenol.
 8. The composition asdefined in claim 5, containing from 0.005 to 20 percent by weight ofeach of said at least one developer and said at least one coupler. 9.The composition as defined in claim 5, further comprising at least onedirect dye compound.
 10. The composition as defined in claim 5,consisting of a hair colorant.
 11. The composition as defined in claim5, wherein said N-benzyl-m-phenylenediamine derivative is selected fromthe group consisting of4-amino-2-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,4-amino-2-{[5-amino-4-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,2-[4-amino-2-(3,5-diamino-benzylamino)phenoxy]ethanol,2-[4-amino-2-(4-dimethylamino-benzylamino)-phenoxy]-ethanol,2-[4-amino-2-(4-methoxy-benzylamino)-phenoxy]-ethanol,2-(4-amino-2-benzyl-aminophenoxy)-ethanol,2-{4-amino-2-[(pyridin-2-ylmethyl)-amino]-phenoxy}-ethanol,2-[4-amino-2-(2-methoxy-benzylamino)-phenoxy]-ethanol,2-[4-amino-2-(2-amino-benzyl-amino)phenoxy]-ethanol,3-[(4-{[5-amino-2-(2-hydroxy-ethoxy)-phenylamino]-methyl}-phenyl)-(2-cyanoethyl)-amino]-propionitrile,2-[4-amino-2-(4-amino-benzylamino)-phenoxy]ethanol,2-[(4-{[5-amino-2-(2-hydroxyethoxy)phenyl-amino]methyl}-phenyl)-(2-hydroxyethyl)amino]-ethanol,2-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-benzene-1,4-diol,2-[4-amino-2-(4-nitrobenzylamino)-phenoxy]-ethanol,2-[4-amino-2-(3-aminobenzylamino)-phenoxy]-ethanol,2-(4-{[5-amino-2-(2-hydroxy-ethoxy)phenyl-amino]-methyl}-phenoxy)-ethanol,N-(4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenyl)-acetamide,4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]methyl}-phenol,3-{(5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenol,2-{[5-amino-2-(2-hydroxy-ethoxy)-phenylamino]-methyl}-phenol,4-{[5-amino-2-(2-hydroxyethoxy)-phenyl-amino]-methyl}-benzoic acid,2-[4-amino-2-(2-morpholin-4-yl-benzylamino)-phenoxyethenol,3-[4-amino-2-(3,5-diamino-benzylamino)phenoxy]-propanol,3-[4-amino-2-(4-dimethylaminobenzylamino)-phenoxy]-propanol,3-(4-amino-2-(4-methoxybenzylamino)-phenoxy]-propanol,3-(4-amino-2-benzlamino-phenoxy)-propanol,3-{4-amino-2-[(pyridin-2-ylmethyl)-amino]phenoxy}-propanol,3-[4-amino-2-(2-methoxybenzylamino)phenoxy]-propanol,3-[4-amino-2-(2-amino-benzylamino)phenoxy]-propanol,3-[4-amino-2-(4-aminobenzyl-amino)-phenoxy]-propanol,3-[(4-{[5-amino-2-(2-hydroxyethoxy)-phenylamino]-methyl}-phenyl)-(2-hydroxyethyl)amino]propanol,3-[4-amino-2-(4-nitrobenzyl-amino)-phenoxy]-propanol,3-[4-amino-2-(3-aminobenzylamino)-phenoxy]-propanol,3-(4-{[5-amino-2-(2-hydroxyethoxy)phenylamino]-methyl}-phenoxy)-propanol,4-{[5-amino-2-(3-hydroxypropoxy)phenylamino]-methyl}-phenol,2-{[5-amino-2-(3-hydroxy-propoxy)phenylamino]-methyl}-phenol,2-{[5-amino-2-(3-hydroxypropoxy)-phenylamino]-methyl}-phenol,3-[4-amino-2-(2-morpholin-4-yl-benzylamino)-phenoxy]-propanol,N³-benzyl-1,3-diamino-4-(2-methoxyethoxy)-benzene,N³-(3-aminobenzyl)-1,3-diamino-4-(2-methoxyethoxy)-benzene,N³-(2-aminobenzyl)-1,3-diamino-4-(2-methoxyethoxy)-benzene,N³-(4-amino-benzyl)-1,3-diamino-4-(2-methoxyethoxy)-benzene,3-{[5-amino-2-(2-methoxy-ethoxy)-phenylamino]methyl}-phenol,2-{[5-amino-2-(2-methoxyethoxy)-phenyl-amino]-methyl}phenol,4-{[5-amino-2-(2-methoxy-ethoxy)-phenylamino]-methyl}-phenol,N³-benzyl-1,3-diamino-4-methoxybenzene,N³-(3-aminobenzyl-1,3-diamino-4-methoxybenzene,N³-(2-amino-benzyl)-1,3-diamino-4-methoxy-benzene,N³-(4-aminobenzyl)-1,3-diamino-4-methoxybenzene,3-{[5-amino-2-methoxy-phenylamino]-methyl}-phenol,2-{[5-amino-2-methoxy-phenylamino]-methyl}-phenol,4-{[5-amino-2-methoxy-phenyl-amino]-methyl}-phenol,N³-benzyl-1,3-diamino-4-fluorobenzene,N³-(3-aminobenzyl)-1,3-diamino-4-fluorobenzene,N³-(2-aminobenzyl)-1,3-diamino-4-fluorobenzene,N³-(4-amino-benzyl)-1,3-diamino-4-fluorobenzene,3-{[5-amino-2-fluoraphenylamino]-methyl}-phenol,2-{[5-amino-2-fluorophenyl-amino]-methyl}-phenol, and4-{[5-amino-2-fluorophenylamino]methyl}-phenol.